Watercraft are often powered by inboard or outboard motors which have internal combustion engines as their power source. The motor includes a water propulsion device, generally a propeller, which is driven by the engine. Conventionally, a transmission is provided between the engine and propeller for selectively driving the propeller in forward or reverse, or for not driving the propeller (i.e. neutral).
A throttle associated with the engine and a transmission control are commonly combined, there being a combined throttle and shift lever which controls both the angle of a throttle valve associated with an air intake of the engine and transmission position. This arrangement has the disadvantage that engine stall sometimes occurs.
In particular, when the shift lever is moved so that the throttle moves from an open to generally closed state, little air is provided to the engine in relation to fuel. If the shift lever is further moved to shift the transmission, a load may be induced upon the propeller, and thus the engine. This load, coupled with the fuel rich mixture, may cause the engine to stall. This situation may arise, for example, when an operator has the shift lever positioned in a high speed forward position and then moves the lever quickly back through neutral and then into a reverse position.
It is an object of the present invention to provide a control for a marine propulsion unit which controls the engine thereof dependent upon movement of a combined throttle and shift lever, thereby resulting in smooth engine operation.